In electrical engineering, any stationary device or electrical system that serves for supplying energy to mobile, battery-operated units, machines or motor vehicles by way of simple setting or insertion without it being necessary for the energy storage—for example the traction battery of an electric automobile—to be removed compulsorily is referred to as a charging station. Charging stations for electric automobiles are also sometimes referred to as “electricity charging stations” and can comprise a plurality of charging points.
Known here in particular are direct-current fast charging/high-performance charging (HPC) systems such as the so-called combined charging system (CCS), which is widespread in Europe. In the case of direct-current charging of the generic type, direct current is fed from the charging column directly into the vehicle and, for this purpose, is provided by way of a powerful rectifier from the electricity network or by way of large buffer accumulators at solar charging stations, for example. Situated in the vehicle is a battery management system, which communicates with the charging column directly or indirectly in order to adapt the current intensity, or to terminate the process when a capacity limit is reached.
The power electronics system is usually located in this case in the charging column. Since the direct-current connections of the charging column are connected directly to corresponding connections of the traction battery, it is possible for high charging currents to be transmitted with little loss, which allows short charging times.
In the various charging stations used worldwide, a wide variety of topologies are used for the power electronics system. State safety standards, such as DIN EN 61851-23, in this case occasionally require a galvanic isolation of the charging columns. Said galvanic isolation can be performed in the various charging columns in a wide variety of ways, for example by way of a separate transformer, and also within various converters, such as an AC/DC rectifier having a transformer, for example. A very small design that takes up little space and has a low weight is desirable for galvanic isolation.
Most modern charging columns implement a galvanic isolation at the input converter, the AC/DC converter having an integrated or upstream transformer. Others produce the galvanic isolation in a DC/DC converter as well. To this end, output-side DC/DC converters are usually used; however, these are very expensive due to high powers. Further solutions make provision for the use of the galvanic isolation from the transformer in the network connection. It is also possible for an additional separate transformer to be added on the AC side.
DE102014013039A1, US2013162032A, US2013175990A and US2015375628A, all of which are incorporated by reference herein, each disclose a charging column for an electric vehicle having a space-saving construction and galvanic isolation, for which purpose a DC/DC converter is sometimes provided. The charging columns according to US2013175990A and US2015375628A each contain a plurality of converters, among which is an AC/DC converter.